1. Field of the Invention
The invention relates to photography lights, and particularly to photography lights for providing "fill" illumination.
In the filming process with a film or video camera, there is need for adjustable lighting equipment which remains cool in temperature while allowing the photographer to continuously change the light value and intensity without changing the beam angle or color temperature.
2. Description of Related Art
Most conventional lights accomplish a change in intensity by either varying the position of a bulb relative to the reflector or by varying the voltage to the bulb.
FIGS. 1 and 2 show arrangements of light fixtures which produce, respectively, a wide-angle and a spot light. While these arrangements change the intensity of light falling on an object in the photographing field, as compared to the spot light, the wide-angle light sheds a significant amount of light on the surrounding area thereby changing the balance of light in this surrounding area.
There are, however, lights which accomplish this change in intensity without changing the beam angle or color temperature. These lights accomplish this change in intensity by changing the reflectance of the reflector of the lighting arrangement from white to black, thus changing the amount of light emitted from the arrangement.
U.S. Pat. No. 4,200,902 to Intrator discloses a photography light which includes alternate black and white strips arranged behind a light source for controlling the amount of light reflected into the photographing field. The ratio of the area of the black strips to the white strips is adjustable by the photographer to effectively vary the intensity of the light into the photographing field.
An arrangement known in the prior art includes a plurality of rods arranged behind a light source as in the patent to Intrator. As shown in FIG. 3, the rods are formed such that half of the surface, around the circumference thereof, is a white, reflective color, while the other half of the surface is a black absorptive color. By controlling the rotational position of the rods in synchronism, the photographer is able to control the intensity of the light into the photographing field.
Another arrangement of the prior art light fixtures, as shown in FIG. 4, positions controllable shutters in front of the light fixture to control the amount of light emitted therefrom.
While the above light fixtures effectively control the intensity of the light into the photographing field, each of these fixtures produces an irregularity in the intensity of the light which may show up in the photographing field as an alternating array of light and dark stripes. In other words, neither of these lights produces uniform illumination. In addition, since the illuminating light is provided directly by bulb(s), the above light fixtures radiate a great deal of heat into the photographing field.